id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
3922	formfield_callback in form_for_model also changes refering model	Jure Cuhalev <gandalf@…>	Philippe Raoult	"Using formfield_callback with newforms form.form_for_model will also change the model you are refering to.


{{{
def CategoryCallback(f, **kwargs):
    if not ""cat_"" in f.name:
      f.name = 'cat_'+f.name
    return f.formfield(**kwargs)

>>> w = Writer(name='Bob Woodward')
>>> Article(headline='Test article', pub_date=datetime.date(1988, 1, 4), writer=w, article='Hello.')
<Article: Test article>

>>> ArticleForm = form_for_model(Article, formfield_callback=CategoryCallback)
>>> f = ArticleForm(auto_id=False)
>>> print f
<tr><th>Headline:</th><td><input type=""text"" name=""cat_headline"" maxlength=""50"" /></td></tr>
<tr><th>Pub date:</th><td><input type=""text"" name=""cat_pub_date"" /></td></tr>
<tr><th>Writer:</th><td><select name=""cat_writer"">
<option value="""" selected=""selected"">---------</option>
</select></td></tr>
<tr><th>Article:</th><td><textarea name=""cat_article""></textarea></td></tr>
<tr><th>Categories:</th><td><select multiple=""multiple"" name=""cat_categories"">
</select><br /> Hold down ""Control"", or ""Command"" on a Mac, to select more than one.</td></tr>
>>> w = Writer(name='Bob Woodward')
}}}

but then doing this one (same one as in the beginning):


{{{
>>> Article(headline='Test article', pub_date=datetime.date(1988, 1, 4), writer=w, article='Hello.')
}}}

fails with:

{{{
    Traceback (most recent call last):
      File ""/Users/gandalf/django/django_src/django/test/doctest.py"", line 1243, in __run
        compileflags, 1) in test.globs
      File ""<doctest modeltests.model_forms_callback.models.__test__.API_TESTS[16]>"", line 1, in ?
        Article(headline='Test article', pub_date=datetime.date(1988, 1, 4), writer=w, article='Hello.')
      File ""/Users/gandalf/django/django_src/django/db/models/base.py"", line 166, in __init__
        raise TypeError, ""'%s' is an invalid keyword argument for this function"" % kwargs.keys()[0]
    TypeError: 'writer' is an invalid keyword argument for this function
}}}

I have attached more comprehensive test derived from modeltests/model_form. I belive that form_for_model with callback should not affect the actual model. It is also not clear if by doing my approach .save() should still work normally or is up to the developer to rename fields back to the way they were originally defined."		closed	Forms	dev		fixed	form_for_model	gandalf@… cgrady@…	Accepted	1	0	0	0	0	0